Computer communication system for communication via public networks

1. A computer communication system, comprising a client computer running an operating system with a built-in virtual private network (VPN) client and located in a public network, at least one server computer located in a corporate network, a web server remote from said client computer, an SSL or IPSec gateway computer located in said corporate network, said SSL or IPSec gateway comprising a packet filter configured to limit access to and from the client computer to resources in the corporate network, and a VPN server computer located in said corporate network, wherein the computer communication system is configured to provide a safe VPN communication connection between said client computer and at least one of said server computers: wherein said client computer, using a WEB browser over the Internet, downloads a configuration file having parameters for configuring the built-in VPN client and an executable program/applet type application from said web server that is stored on a non-transitory computer readable medium to be run on the client computer, the executable program/applet type application being executable within the client computer's WEB browser, and wherein said downloaded application is programmed to perform the following functions: a) automatically configuring and starting the built-in VPN client on said client computer by specifying a loopback address as the destination address, on which said downloaded application accepts a L2TP-/PPTP connection from said built-in VPN client for communications between the client computer and the at least one server computer, b) establishing and handling the L2TP-/PPTP-connection with said built-in VPN client thereby obtaining PPP packets containing payload data of locally running applications running locally on the client computer, and c) establishing an SSL or IPSec encrypted tunnel connection from said client computer to said SSL or IPSec gateway computer which is part of said corporate network, wherein all of the PPP packets containing the payload data generated by the built-in VPN client are encrypted at the client computer by the downloaded application, and sent through said tunnel connection to the SSL or IPSec gateway computer and are then at the other end of the tunnel connection decrypted and forwarded via the SSL or IPSec gateway computer to the VPN server computer in said corporate network.

2. A computer communication system according to claim 1 , wherein the SSL or IPSec encrypted tunnel connection between the client computer and the SSL or IPSec gateway computer is secured by use of a SSL or IPSec encryption protocol.

3. A computer communication system according to claim 1 , wherein at the client computer a process is started by the downloaded applet type application which causes the client computer to establish said SSL or IPSec encrypted tunnel connection.

4. A computer communication system according to claim 3 , further comprising an operating system as the client computer operating system, wherein the configuration of said built-in VPN client is done by the downloaded applet type application through a downloaded configuration file and said VPN client is started by using the operating system function “CreateProcess”.